Piedmon
Saiyajin Quaterback
I think the key difference (sorry if someone else already raised this point) is that in Marvel the cosmically all-powerful demigods aren't headliners. Think of Marvel's big, best known characters: Spider Man, Wolverine, Captain America, DAREDEVIL.... with the possible exception of The Hulk, Marvel's biggest characters are either street-level or only marginally above. (I say "possible" because Hulk's power levels seem to bounce up and down depending on the needs of the story.)
Silver Surfer, Genis-Vel, the Sentry, Dr. Strange.... these "cosmic power" guys are much less prominent. None of them seem to be able to hold a continuous series. I doubt we'll be seeing them in a movie anytime soon.
DC, by contrast, has its most powerful characters in the most prominent roles. Superman, Wonder Woman, and The Flash are all household names. This goes a long way to giving the impression that the DC Universe is home to the strongest heroes.
That's my two cents. It's all about impression, atmosphere, not fact.